Saturday, March 14, 2015

DevOps with Windows - Chocolatey on AWS

Conceptually Package manager is well understood space for
someone having slightest understanding of how *nix environment get’s managed,
but when it comes to windows it was untracked space till recently. This was
piece of stack which was ironically missing for so long that once you get hands
on you will feel how on earth you were living without it.NuGet and Chocolatey are the two buzz
words making lots of noises and deemed as the future for windows server
management.

What Is Chocolatey?

Chocolatey builds on top of NuGet packaging format to
provide a package management for
Microsoft Windows applications , Chocolatey iskind of yum or
apt-get but for windows. Its CLI based and can be used to decentralize
packaging. It has a central repository
located at http://chocolatey.org/.

If you have ever used windows build in provider you probably
be aware of the issues it has. It doesn’t really do versioning and seems misfit
for upgrading. Any organization looking for long term solution to ensure that
latest versions are always installed for them build in package provider may not be
the recommended option .Chocolatey takes care of all this with very little
effort. In contrast to default provider which has no dependency Chocolatey
requires your machine to have Powershell 2.0 & .Net framework 4.0 installed.
Installation of packages from Chocolatey is one command line that reaches out
to internet and pulls it down. That would be version-able and upgradable; you
can specify this version of package and that that’s what gets installed.

Recommended way of Chocolatey installation is by executing
PowerShell script.

Chocolatey With AWS

AWS offers windows instances with both their offering;
under IAAS you can launch windows instance as EC2, whereas with PAAS you can get
that via Elastic beanstalk.

Using Cloud Formation:

Using ‘cfn-init’ AWS Cloud Formation supports the download
of files and execution of commands on Windows EC2 instance. Bootstrapping of
Windows instance using Cloud Formation is lot simpler than any other ways. We
can leverage this offering to install Chocolatey while launching the server
using CFT.While doing this using Cloud formation we have to execute PowerShell.exe and provide the install command to that.One thing to be take care of that Chocolatey installer and
the packages it installs may modify the machine's PATH environment variable.
This adds complexity since subsequent commands after these installations are
executed in the same session, which does not have the updated PATH. To overcome
this, we utilize a command file to set the session's PATH to that of the
machine before it executes our command. We will create a command file
'ewmp.cmd' to execute a command with the machine's PATH, and then we will proceed
with Chocolatey and any other installation. With below sample we will be
installing Chocolatey and then install Firefox with Chocolatey as provider.

AWS Elastic Beanstalk supports the downloading of files and
execution of commands on instance creation using container customization. We
can leverage this feature to install Chocolatey.

The aforementioned installation can get translated into AWS
Elastic Beanstalk config files to enable use of Chocolatey in Elastic Beanstalk.
The change while doing using Elastic Beanstalk; we will create YAML .config
files inside the .ebextensions folder of our source bundle.